Cutter pick unit



M. S. MOORE CUTTER PICK UNIT Dec. 5, 1933.

2 Sheets-Sheet 1 i i l Fi .4. I

Flled Sept.- 22. 1932 F5 mi is *0 ma/Jan g Dec. 5, 1933. 5. MOORE 1,938,530

CUTTER PICK UNIT Filed Sept. 22, 1932 2 Sheets-Sheet 2 2 Fig.9 1 1 .11.

I 8%r\ 6 2T +X j 771.5. Tfiavf Patented Dec. 5, 1933 UNITED STATES PATENT OFFICE CUTTER PICK UNIT British company Application September 22, 1932, Serial No. 634,432, and in Great Britain October 3, 1931 Claims.

This invention relates to coal cutting machines and the like, and it has particular reference to cutter picks and pick boxes such as are used in cutting machines of the chain type.

Various means have been proposed in order securely to retain the cutter picks in their boxes, the method usually resorted to consisting in fastening the picks in rectangular holes in the boxes by means of cup-pointed set screws which 10 are driven through holes in the sides of boxes at right angles to the pick stems. Being of hardened steel, the screws bite into the softer metal of the pick stems and thus lock them in the proper position. It is well known that considerable force is required to sink the cup point into the pick. The insertion and withdrawal of the picks and screws are slow and laborious work, and the screws are liable to get damaged or broken when they are-driven home. They may m also work loose when in use.

The objects of my present invention are to overcome these inconveniences and provide a means whereby the cutter picks can be securely fixed in position, easily withdrawn when necessary, and adjusted as may be required to suit the conditions of cutting.

With these objects in view, in accordance with my invention, I provide a cutter pick having a stem tapered transversely from'front to back,

'0 and with this pick I associate a clip having shanks likewise tapered transversely from front to back, adapted to fit between the walls of the pick-box and the sides of the stem. Thus, when the pick and its enclosing clip are inserted toa gether in the hole in the pick box, pressure on the pick point will initiate a wedging action and the harder the point is pressed, the more firmly the pick will be held. r

The clip is conveniently made U-shaped and may be formed from half-round strip metal, its

flat inner faces being transversely convergent to conform to the wedge-shaped pick stem.

In one form of my invention, the pick stem is also tapered longitudinally from point to base, thus being tapered essentially in two directions. The shanks of-the clip then are tapered accordingly so that a wedging action takes place when the pick is pressed inwardly as well as rearwardly.

Means are conveniently provided for interlocking the pick with the clip to preclude accidental or unintentional disengagement. This may be attained by providing the pick and clip with suitable projections and/or recesses adapted for mutual engagement.

The pick box holes may be of circular crosssection or of any other suitable shape adapted to accommodate the clip with the pick fitted therein. With circular holes, means as a pinching screw may be provided for locking the clip and pick against rotation in the pick box. Or diametrically opposed slots for engaging the front or both the front and back edges of the end of the stem may be formed in the wall of the hole.

In order to afford a very close contact and grip between the pick box and the clip having the pick therein, I may provide serrations or teeth on the outer side of the clip, or on the inside wall ofthe hole in thepick box. To this end I may conveniently provide said hole with an internal screw-thread which is preferably made by means of a tapered tap.

Various embodiments of my invention are illustrated by way of example in the accompanying drawings in which:

Fig. 1 is a rear elevation of a wedge-shaped cutter pick and Fig. 2 a similar view of the cooperating clip.

Fig. 3 is a front elevation of said pick and clip inserted in a pick box hole. 30

Fig. 4 is a side elevation of the pick and clip as inserted in the hole and Fig. 5 is a similar view showing the pick in operative position.

Fig. 6 is a cross sectional view, as on line VI-VI of Fig. 4, illustrating the composite element in the pick box hole. Fig. 7 is likewise a cross sectional view showing a modification.

Fig. 8 shows a pick box in sectional elevation.

Fig. 9 is a front elevation of another form of cutter pick, Fig. 10 being a cross-section on line XX of Fig. 9.

Fig. 11 is a front elevation of a clip adapted to co-operate with the pick shown in Fig. 9 and Fig. 12 is an end view of said clip.

Fig. 13 is a sectional elevation of a pick box with a pick and clip fitted therein and Fig. 14 is a cross-sectional view taken on line XIVX[V of Fig. 13.

In' all the figures of the drawings, 1 is the stem of the pick which is tapered from front to back and is provided at one end with a point 2 of suitable shape. The clip which is adapted to co-operate with the pick comprises two shanks 3 which may comprise separate strips, but are preferably made of a single resil- 5 ient strip of metal, herein shown to be of half round or segmental cross-section, bent to U- shape. The inner faces of the shanks 3 are taperedat 4 to conform with the taper of the pick stem.

fhe pick and clip thus form together an expansible composite eiement which is adapted to be inserted in a holder, as a pick box, the arrangement being such that under working conditions the pick stem acts as a wedge and expands the clip with the holder, thus providing a very firm grip.

Co-operating projections and recesses are preferably provided in adjacent faces of the pick and clip in order to preclude accidental or unintentional disengagement thereof. Thus, as illustrated in Figs. 1 to 5, the stem 1 may have lateral swellings or projections 5 in a portion remote from the point such swellings being conveniently formed by indenting the rear face of the pick as shown at.6. Corresponding recesses or slots '7 being provided in the inner faces of the clip, the swellings 5 will fit in said recesses when the pick and clip are assembled, whereby same are firmly interlocked against mutual longitudinal motion.

The pick box 8 adapted to accommodate the pick and clip has a hole 9 of circular or other suitable shape. I preferably use a circular hole provided with two diametrically opposed rectangular slots 10 (Figs. 4 to 6 and 8). Ihe clip and pick being inserted in the position shown in Fig. 4, the pick takes up, in operation, a slightly inclined position as illustrated in Fig. 5, the bottom end of the stem 1 projecting into the front slot 10, while its upper end forced as a wedge between the shanks of the clip and into the rear slot, at the same time looking the pick against rotation in the pick box. Owing to said wedge action and the resiliency of its shanks, the clip 3 expands and accommodates itself to the best grip. The harder the point is pressed, the firmer the pick is held. To release it, however, it is only required to apply reverse pressure on the bent portion of the clip, when the pick and clip may be easily withdrawn together.

If desired, serrations or teeth may be formed on the outer sides of the shanks or strips in order still further to increase the grip'in the box. Or the teeth or the like may be provided on the inside wall of the pick box hole. To this effect I may conveniently provide'said hole with in internal screw thread 11. As shown in Figs. 3 and 8, the hole may e caused to upwardly by inwardly screw-threading same with a tapered tap. By this means a slight degree of distortion or splaying of the metal of the clip is caused to take place under working stresses, thereby allowing the pick to assume the proper angle relatively to the pick box while preventing it from being driven further into the clip by any force acting vertically upon its point.

The threading of the pick box holes also serves securely to hold the clips and picks in position against centrifugal force upon mo-. tion of the chain being reversed, said motion tends to cause the picks to be tilted forward into a loose position, as frequently happens during a cut.

It will be seen'that with the shape of hole illustrated in Figs. 6 and 8, the composite element comprising the pick and clip can be insorted for use in either direction of movement, of the pick box, and will be equally effective in both cases. If the holes in the pick boxes are of uneven length or width, this can be compensated for by pushing the clip'mcre or less deeply into the hole and wedging the pick in the proper position to suit the conditions of cutting. When a circular hole is used without slots 10, as shown in Fig. 7, means as a pinching screw 12 are provided to hold the clip and with it the pick against rotation. In Fig. 7 the sides of the shanks are shown to be provided with recesses or grooves 13 to accommodate the end of screws 12. It thus will be understood that the clip and pick are applicable to boxes of standard type, without change.

In the form of my invention shown in Figs. 9 to 14, the stem 1 of the pick is tapered not only transversely but also longitudinally from the point down. At the end remote from the point 2 a toe formation 14 is provided, jutting out from the back, but instead of tapering as does the stem, this end retains a rectangular shape so that, on the sides, shoulders are formed at 15 by the change from tapered to rectangular section. V I

The co-operating clip, as shown in Figs. 11 and 12, is similar to that illustrated in Fig. 2, except that for the greater part of their length, the inner faces 16 of the shanks 3 are tapered both transversely and longitudinally, whilst near the bent portion of the U the said faces are parallel, in such manner that a step 17 is formed on the interior of each shank as the section changes from parallel to taper.

When the pick stem is placed in the U-clip their tapered faces come into mutualengagement, whilst the shoulders 15 coming. into contact with the clip steps 1'7 link the two parts together in the longitudinal direction. The pick box shown in Figs. 13 and 14 has a hole 9 with opposed rectangular slots 10 as above described, this shape being particularly suited to accommodate the pick with projecting toe piece 14.

It will be understood that constructional details of my invention may be further modified without departing from its scope as defined by the appended claims. Thus, for example, the clip may comprise two independent strips or shanks instead of a single U-shaped member, and the section of the loose or joined shanks may be made quadrangular to fit a rectangular hole in the pick box. I

I claim: V

1. In combination in a cutter pick unit, a pick having a wedge shaped stem, and a clip open back and front having a pair of shanks with convergent inner faces to accommodate said pick stem. H 2. In combination in a cutter pick unit, a pick having a wedge shaped stem tapering from front to back, and an expansible clip comprising a pair of elongated shanks extending longitudinally of said stem, said shanks having inner faces converging from front to back in engagement with theside faces of said pick stem.

3. In combination in a cutter pick unit, a pick having a stem tapering from front to back and from point to base, and a resilient clip having inner faces converging from front to back and from point to base in engagement with said pick stem.

4. In combination in a cutter pick unit, apick having a stem tapering transversely, and an expansible L! shaped clip extending longitudinally of said sten said clip having inner faces converging transversely in engagement with the sides of said pick stem. 7

-5. In combination in a cutter pick unit, a pick having astem tapering from front to back, and

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a clip formed of a single resilient strip'of metal of half-round section bent to U shape, said clip having inner faces converging from front to back to engage the sides of said pick stem.

6. In combination in a cutter pick unit, a'pick having a wedge shaped stem, a clip formed of a single resilient strip of metal bent to U shape, said clip having convergent inner faces to engage said pick stem, and projections and depressions in the adjacent faces of said pick and clip to interlock said pick and clip in the longitudinal direction.

7. In combination in a cutter pick unit, a pick having a wedge shaped stem, an expansible clip formed of two parallel shanks extending longitudinally of said stem and having convergent inner faces in fitting engagement therewith, said clip being open at the back, and a pick box having a hole therein to accommodate said clip and pick.

8. In combination in a cutter pick unit, a pick having a stem tapering from front to back, an expansible clip open back and front formed of two parallel shanks extending longitudinally of said stern and having their inner faces converging from front to back to engage said pick stem, means for interlocking said pick and clip in the longitudinal direction, and a pick box having a hole therein to accommodate said interlocked I pick and clip.

9. In combination in a cutter pick unit, a pick having a stem tapering transversely and longitudinally, a clip formed of two parallel shanks having inner faces converging transversely and longitudinally to engage said pick stem, means for interlocking said pick and clip in the longitudinal direction, and a pick box having a hole therein to accommodate said interlocked pick and clip.

10. In combination in a cutter pick unit, a pick having a stem with convergent sides, a U shaped clip formed of half-round strip metal having convergent inner faces to engage said pick stem, projections and recesses in the adjacent faces of said pick stem and clip to interlock said pick and clip in the longitudinal direction, and a pick box having a circular hole therein to accommodate and grip said interlocked pick and clip.

11. In combination in a cutter pick unit for mining machines, a pick of tapering cross-section, a pick box, and an expansible clip adapted to be interposed between the sides of said pick and the inner walls of said box and to hold the I pick in a grip tightening in proportion to increased pressure on the pick point.

12. In combination in a cutter pick unit for mining machines, a pick having a stem with converging sides, a pick box, and an expansible U-shaped clip arranged longitudinally of said pick, the shanks of said clip being interposed between the converging sides of said pick stem and the inner walls of said box, the size of said box being sufficient to allow of a wedging movement of the pick and consequent expansion of the clip.

13. In combination in a cutter pick unit, a pick having a wedge shaped stem, a U shaped clip formed of a resilient metal strip of segmental cross-section, said clip having convergent inner faces to engage said pick stem, and a pick box having therein an inwardly screwthreaded hole to accommodate and grip said clip and pick stem.

14. In combination in a cutter pick unit, a

pick having a wedge shaped stem, an expansible clip 'open back and front formed of two parallel shanks of half round cross section having convergent inner faces to engage said pick stem, a pick box having therein a circular hole, and longitudinal slots in the wallet said hole adapted to be engaged by the inner end of said pick.

15. In combination in a cutter pick unit, a pick having a stem with convergent sides, a clip formed of two parallel shanks of halfround cross-section having convergent inner faces to engage said pick-stem, and a pick box having therein an inwardly screwthreaded, outwardly flaring hole to accommodate and resiliently to grip said clip and pick.

16. In combination in a cutter pick unit, a pick having a stem tapering transversely and longitudinally, a clip formed of two parallel shanks of segmental cross-section having inner faces converging transversely and longitudinally to engage said pick stem, means for interlocking said pick and clip in the longitudinal direction, a pick box having therein a circular hole to accommodate and grip said interlocked clip and pick, and means for holding said interlock clip and pick against rotation in said pick box hole.

17. In combination in a cutter pick unit, a pick having a stem tapering from front to back, a clip formed with two parallel shanks of segmental cross-section having inner faces converging from front to back to engage said pick stem, projections and depressions in the adjacent faces of said pick and clip to interlock said pick and clip in the longitudinal direction, a pick box having therein a circular hole to accommodate and grip said interlocked clip and pick, a recess in said clip, a tapping through the wall of said pick box, and a set screw in said tapping and in engagement with said recess to hold said interlocked clip and pick against rotation in said pick box.

18. In combination in a cutter pick unit, a pick having a stem tapering transversely and longitudinally, a clip formed of a single resilient strip of metal of segmental cross-section bent to U shape, said clip having convergent inner faces to engage said pick stem, a projection in said clip and a depression in said pick stem to interlock said clip and pick in the longitudinal direction, and a pick box having therein a hole to accommodate said clip and diametrically opposed slots to accommodate the inner end of said pick stem.

19. In combination in a cutter pick unit, a pick having a stem tapered throughout the greater part of its length, a projecting toe of rectangular cross-section at the end of said stem remote from the pick point, and a clip formed of two parallel shanks having inner faces converging throughout the greater part of their length to engage said pick stem and a parallel terminal portion remote from the points of said shanks, said portion interlocking with said projecting toe and holding said pick and clip against relative longitudinal motion.

20. In combination in a cutter pick unit, a pick having a stem tapered transversely and longitudinally throughout the greater part of its length, a projecting toe of rectangular crosssection at the end of said stem remote from the pick point, a clip formed of two parallel half-round shanks, said shanks having inner faces converging transversely and longitudinalbox having a round hole to accommodate said half-round clip shanks with the pick stem engaged thereby and two diametrically opposed slots to accommodate said rectangular projecting pick stem toe.

' MATTHEW SMITH MOORE. 

